[avr-gcc-list] Re: How to force GCC to not to remove "nop" statements ?

[Gene Smith]

Ruud Vlaming wrote:
> On Friday 06 March 2009 01:34, Gene Smith wrote:
> > Vincent Trouilliez wrote:
> > > On Thu, 19 Feb 2009 11:14:40 -0700
> > > "Weddington, Eric" <address@hidden> wrote:
> > >
> > > > If you are using WinAVR 20081205 then you can use one of the new builtin 
> > > > functions:
> > > > void __builtin_avr_delay_cycles(unsigned long __n);
> > > Hmm, sweet !
> > > "Unfortunately" I am on Linux so no WinAVR for me ! ;-)
> > Beginner question: If I build the avr-gcc-4.3.2 toolchain on linux using 
> > all the WinAVR (sourceforge) patches, as seems to be done in the femtoos 
> > scripts mention on "freaks", will I have the same features (such as 
> > function mentioned above) on linux as winavr provides on windows? Will 
> > (or can) they produce identical binaries?
>
> Yes, they will, given the same patches are used. Note that the script is not 
> intelligent enough to detect new patches as the appear, and include a few
> patches which were (at the time i published the script) not yet in released,
> or are of my own making (and may never be released)
>
> Furthermore the script builds gcc-4.3.3 and not 4.3.2 so this could
> make a difference too.
>
> Ruud

I used your script and modified the gcc version back to 4.3.2 and I get 
almost the same results on fedora8 as XP. The avr-size output is the 
same and the build produces hex files that match. Also, the *.lss files 
(objdump result) *almost* match except for the ."debug_" sections. Don't 
know why these few lines differ (or what they are really for):

$ diff -Naur main.lss ../main.lss
--- main.lss    2009-03-06 17:55:48.065959800 -0500
+++ ../main.lss 2009-03-06 17:30:01.000000000 -0500
@@ -15,15 +15,15 @@
                   CONTENTS, READONLY, DEBUGGING
   5 .debug_abbrev 00001324  00000000  00000000  00007612  2**0
                   CONTENTS, READONLY, DEBUGGING
-  6 .debug_line   00003a2f  00000000  00000000  00008936  2**0
+  6 .debug_line   00003df5  00000000  00000000  00008936  2**0
                   CONTENTS, READONLY, DEBUGGING
-  7 .debug_frame  000006b0  00000000  00000000  0000c368  2**2
+  7 .debug_frame  000006b0  00000000  00000000  0000c72c  2**2
                   CONTENTS, READONLY, DEBUGGING
-  8 .debug_str    00000de7  00000000  00000000  0000ca18  2**0
+  8 .debug_str    00000dd1  00000000  00000000  0000cddc  2**0
                   CONTENTS, READONLY, DEBUGGING
-  9 .debug_loc    00001b35  00000000  00000000  0000d7ff  2**0
+  9 .debug_loc    00001b35  00000000  00000000  0000dbad  2**0
                   CONTENTS, READONLY, DEBUGGING
- 10 .debug_ranges 00000018  00000000  00000000  0000f334  2**0
+ 10 .debug_ranges 00000018  00000000  00000000  0000f6e2  2**0
                   CONTENTS, READONLY, DEBUGGING

The remainder of this huge file matches!

Also, I see that I do have the builtin function mentioned above on the 
linux build so it is not exclusive to winavr.

-gene
p/s: Thanks for answering my questions on the avr-gcc forum too!